Code transmitter



April 25, 1967 HAM, R ET AL 3,316,357

CODE TRANSMITTER 5 Sheets-Sheet 1 Original Filed July 1, 1963 J. H. HAMJR. m/r/g/v TORS J. 1-: RITCHEY H! R. TOLMA N BY A TTORNE V April 25,1967 H AM, J ET AL 3,316,357

CODE TRANSMITTER Original Filed July 1, 1963 5 Sheets-Sheet 2 g a #1 g 0g 3 E o O O 0 33] 0 il 9 3 O O D g k g fi q g ono g 0 Q April 25, 1967 MJR" ET AL 3,316,357

CODE TRANSMITTER 5 Sheets-Sheet 15 Original Filed July 1 1965 UnitedStates Patent l 3,316,357 CODE TRANSMITTER James H. Ham, Jr.,Indianapolis, James F. Ritchey, Carmel, and Warren R. Tolman,Indianapolis, Ind.; said Tolman assignor to Western Electric Company,Inc., New York, N.Y., a corporation of New York, and said Ham and saidRitchey assignors to Bell Telephone Laboratories, Inc., New York, N.Y.,a corporation of New York Original application July 1, 1963, Ser. No.291,770, now Patent No. 3,274,345, dated Sept. 20, 1966. Divided andthis application May 24, 1966, Ser. No. 552,457 2 Claims. (Cl. 179-90)This invention, which is a division of application Ser. No. 291,770,filed July 1, 1963, now Patent No. 3,274,- 345, relates to codetransmitters and particularly to code transmitters operated by means ofpushbuttons.

An illustrative embodiment of the code transmitter of the presentinvention comprises a pushbutton call transmitter including amultifrequency signal generator. The pushbutton call transmittercomprises a cover member having a plurality of holes therein arranged inan array of longitudinal columns and transverse rows. A plurality ofguide collars extend from the topside of the cover member andrespectively encompass the holes, and a plurality of prestressing studsextend from the underside of the cover member. An individual pushbuttonis situated in each of the holes in the cover member, each pushbuttonbeing associated with a diiferent digit which is characterized by twounique frequencies and each pushbutton further being movable between anextended position and a depressed position and being biased toward itsextended position.

A plurality of longitudinal and transverse rotatable shafts arejournaled in the cover member, an individual shaft extending along oneside of each column and each row of pushbuttons. Each shaft has aplurality of projecting levers, and individual levers on eachshaftrespectively extend into the paths of travel of the individualpushbuttons alongside of which the shaft extends, whereby the depressionof an individual pushbutton results in the rotation of a unique pair ofshafts.

A pair of spring contacts for selecting a discrete frequency of aresonant circuit of the signal generator is associated with each shaft.A first contact of each pair is biased against a lever of its associatedshaft and a second contact is biased against a prestressing stud on thecover member, the lever moving the first contact into engagement withthe second contact upon rotation of the shaft.

A displaceable member having a plurality of cam surfaces is associatedwith the transverse shafts. Each cam surface is associated with anindividual shaft and is in juxtaposition with one of the levers of theshaft, the rotation of any one of the transverse shafts displacing thedisplaceable member. The displaceable member extends into engagementwith a switching means for the signal generator, and the displacement ofthe displaceable member results in the operation of the switching means.Thus upon actuation of any one of the pushbuttons a unique pair ofshafts is rotated to close two pairs of frequency selecting springcontacts and displace the displaceable member to operate the switchingmeans in a particular sequence.

A complete understanding of the invention and of these and otherfeatures and advantages thereof may be gained from consideration of thefollowing detailed description taken in conjunction with theaccompanying drawing wherein one embodiment of the invention isillustrated. It is to be expressly understood, however, that the drawingis for the purpose of illustration and description and 3,316,357Patented Apr. 25, 1967 is not to be construed as defining the limits ofthe invention.

In the drawing:

FIG. 1 is a perspective view of a telephone set including a calltransmitter embodying the present invention, the housing of thetelephone set being removed and positioned to one side to provide aclearer view of the call transmitter;

FIGS. 2A and 2B combined are an exploded perspective view of theelements comprising the call transmitter; and

FIG. 3 is a bottom view of the elements of FIG. 2A assembled.

Referring to the drawing and FIG. 1 in particular, a telephone set 12including a call transmitter embodying the present invention is showntherein. The telephone set 12 comprises a base 14 and a handset 15, thehandset when not in use being positioned in a cradle 16 at the rear ofthe base. The base 14 has a forwardly inclined faceplate 18 throughwhich elements of the cal transmitter extend, these elements being tenpushbutons 20 and ten guide collars 22. The upper surface of eachpushbutton 20 is curved convexly, and one of the digits 1 through 0appears thereon, indicating the particular digit that the pushbuttonrepresents.

Turning now to FIGS. 1, 2A, and 3, the call transmitter furthercomprises a cover member 48 having ten square holes 50 therein. Each ofthe holes 50 is encompassed by one of the guide collars 2, the collarsbeing square and extending from the upper surface of the cover member48. The holes 50 are arranged in longitudinal columns and transverserows, and each pushbutton 20 has a square upper end thereof slidablypositioned in one of the holes.

The collars 22 increase the height of the walls defining the holes 50,and the walls taper toward the upper end so that the upper inside edgeof each collar interacts with the upper end of the pushbutton 20positioned therewithin to guide the movement thereof. In addition, thecollars 22 in projecting through the faceplate 18 'of the telephone set12 provide a rigid intermediary between the face plate and thepush-buttons 20 that locates, the call transmitter with respect to thefaceplate and eliminates the possibility of interference between thepushbuttons and the faceplate, thereby assuring free operation of thepushbuttons.

Each pushbutton20 includes a pair of flanges 52 and 54 extendinglaterally therefrom and between the ends thereof, the flange 52 lying ina higher plane than the flange 54. The flanges 52 and 54 extend beneaththe portions of the under surface of the cover member 48 to the sides ofthe holes 50 and thereby limit the upward motion of the pushbuttons 20.The portions of the under surface of the cover member 48 in juxapositionwith the flanges 52 are relieved so that the flanges 52 and 54 engagecorresponding under surfaces simultaneously.

The flanges 52 and 54 of each pushbutton 20 respectively overlie a lever55 of a transverse shaft 56 and a lever 58 of a longitudinal shaft 60,the levers extending laterally from the shafts. An individual transverseshaft 56 extends along one side of each row of pushbuttons 20, and anindividual longitudinal shaft 60 extends along one side of each columnof pushbuttons. Thus when any pushbutton 20 is depressed, the levers 55and 58 of a unique pair of transverse and longitudinal shafts 56 and 60are deflected downwardly.

Each transverse shaft 56 and longitudinal shaft 60 includes journals 62that are respectively accommodated by notches 64 in longitudial sidewalls 65 and transverse side walls 66 depending from the underside ofthe cover member 48. The notches 64 serve as hearings in which theshafts 56 and 60 rotate, and consequently the deflection of the levers55 and 58 of a pair of transverse and longitudinal shafts results in therotation of the shafts.-

The longitudinal side walls 65 are of a lesser height than thetransverse side walls 66 so that the transverse shafts 56 lie in ahigher plane than the longitudinal shafts 60. The transverse andlongitudinal shafts 56 and 60 thereby rotate without interfering withone another.

Each transverse shaft 56 and longitudinal shaft 60 includes a tab 68that extends into a slot 70 in the underside of the cover member 48 tomaintain the shafts in their proper axial position. In addition, eachtransverse shaft 56 has both a contact actuating lever 72 at one endthereof and an operator actuating lever 73 adjacent to one end thereof,while each longitudinal shaft 60 has only a contact actuating lever 74at one end thereof.

Turning now to FIGS. 2A and 2B, underlying the cover member 48 is aframe member 75 and a base member 76. Fasteners 78 secure the basemember 76 to bosses 79 depending from the underside of the cover member48, and the frame member 75 is sandwiched between the base member andthe cover member. To properly locate the frame member 75 with respect tothe cover member 48 and the base member 76, a key 80 and a pin 81extending upwardly and downwardly from the frame member are respectivelyaccommodated by a notch 82 and a sleeve 83 in opposing transverse sidewalls 66 of the cover member and a notch 84 of an orifice 85 in opposingedges of the base member.

The base member 76 has downwardly extending lugs 86 in which fasteners87 are threaded, and the fasteners are employed to secure the basemember and thereby the call transmitter to a support within thetelephone set.

The frame member 75 butts against the bottom edges of the transversewalls 66 and longitudinal walls 65 of the cover member 48 and therebyretains the longitudinal shafts 60 and transverse shafts 56 in thebearing notches 64. In addition, the frame member 75 has an array ofsquare holes 88 therein that receive square lower ends of thepushbuttons 20, the walls defining the holes 88 interacting with thelower ends of the pushbuttons to guide the movement thereof. The holes88 in the frame member 75 are in alignment with the holes in the covermember 48, and the walls defining the holes 88 thereby cooperate withupper inside edges of the collars 22 (FIG. 1) of the cover member todirect the movement of the pushbuttons 20 parallel to the longitudinalaxes thereof.

The underside of each pushbutton 20 has a hole therein and a helicalcompression spring 89 positioned in each hole bears against the basemember 76 to bias the pushbuttons upwardly and normally maintain thepushbuttons in an extended position. When a pushbutton 20 is depressed,the spring 89 is compressed within the hole in the pushbutton and thedownward movement of the pushbutton is arrested by the engagement of theunderside thereof With the base member 76.

Pairs of normally open frequency selecting spring contacts 90 and 91 areinsulatedly secured to the upper surface of the base member 76. Thepairs of spring contacts 90 and 91 are disposed about the periphery ofthe base member 76, and the lower contact of each pair underlies and isprestressed against a prestressing stud 92 depending from the undersideof the cover member 48. The upper contact of each pair of springcontacts 90 underlies and is prestressed against the actuating lever 72of an individual transverse shaft 56, and the upper contact of each pairof spring contacts 91 underlies and is prestressed against the actuatinglever 74 of an individual longitudinal shaft 60. The prestressing of thespring contacts assures the generation of good contact pressure withvery small travel of the spring contacts.

The upper contacts of the pairs of frequency selecting spring contacts90 and 91 respectively act to maintain the levers of the transverseshafts 56 in engagement with underside of the pushbutton flanges 52 andthe levers 58 of the longitudinal shafts in engagement with theunderside of the pushbutton flanges 54, and when the pushbuttons 20 arein their extended position, the upper contacts are spaced from the lowercontacts. However, when any one of the pushbuttons 20 is depressed, thetransverse shaft 56 and longitudinal shaft 60 extending alongsidethereof are rotated, and the respective contact actuating levers 72 and74 of the shafts move the upper contacts of the pairs of spring contactsand 91 associated with the levers into engagement with the lowercontacts. The upper contacts deflect the lower contacts from theirassociated prestressing stud 92, and relative motion occurs between thecontacts that provides a wiping action of the contact surfaces.

It is to be noted that the positioning of the pairs of frequencyselecting spring contacts 90 and 91 around the periphery of the basemember 76 places them out in the open and thereby makes them readilyaccessible for adjustment and cleaning without having to disassemble thepushbutton dial 44. Furthermore, as seen in FIG. 3 from the positions ofthe contact actuating levers 72 and 74 and the studs 92, the covermember 48 overlies the pairs of frequency selecting spring contacts 90and 91 and thereby prevents damage to the spring contacts when the calltransmitter is being handled.

The underside of the frame member 75 includes a channel 93 that extendsalong a longitudinal side thereof, and captured within the channel andbetween the frame member and the base member '76 is a slidablydisplaceable switch operator 94. The operator 94 has four spaced camportions 95 extending upwardly therefrom that respectively extendthrough spaced holes 96 in the channel 93. Each cam portion 95 extendsinto engagement with the operator actuating lever 73 of an individualtransverse shaft 56, and upon the rotation of any one of the transverseshafts by the depression of a pushbutton 20, the operator actuatinglever thereof interacts with the cam portion with which it is inengagement to displace the operator 94 along the channel 93 in thedirection of the arrow in FIG. 2B.

The operator 94 has a contact actuating comb portion 98 extendingdownwardly therefrom that consists of spaced teeth 100, 101, 102, and103. The teeth 100 through 103 extend through a slot 105 in the basemember 76 and into engagement with a common switch 106 secured to theunderside of the base member. The common switch 106 comprises amake-before-break combination consisting of normally closed contacts 108and normally open contacts 110, two pairs of normally closed contacts112 and 114, and a biasing spring 115. The movable contact members ofthe make-before-break combination, the normally closed contacts 112, andthe normally closed contacts 114 respectively extend into juxtapositionwith the teeth 100, 101, and 102 and the biasing spring 115 extends intoengagement with the tooth 103.

The biasing spring 115 biases the cam portions 95 of the operator 94toward the operator actuating levers 73, and thereby tends to maintainthe cam portions in engagement with the levers. The teeth 100, 101, and102 are spaced so that when the operator 94 is displaced by thedepression of a pushbutton 20, the contacts are actuated in thefollowing sequence: the normally closed contacts 114 are opened, thenormally closed contacts 112 are opened, the normally open contacts areclosed, and the normally closed contacts 108 are opened. The sequence isreversed upon the return movement of the operator 94.

From the foregoing description it can be seen that the depression of anypushbutton 20 serves to close one pair of frequency selecting springcontacts 90 and one pair of frequency selecting spring contacts 91 andto operate the common switch 106. The displacement of the operator 94 isarranged so that the pairs of frequency selecting spring contacts 90 and91 are closed before the normally closed contacts 108 of the commonswitch are opened.

Underlying the base member 76 alongside of the common switch 106 is aprinted circuit board 116. A pair of fasteners 117 secure the printedcircuit board 116 directly to the base member 76, and a pair offasteners 117 extend through holes in the base member to secure theprinted circuit board to bosses 118 depending from the cover member 48.The fasteners 117 and 117' extend through dielectric bushings 119mounted in the printed circuit board 116, the bushings having slottedcollars 120 that are forced into holes 120' in the printed circuitboard. The bushings 119, which are thereby held captive in the holes120', space the printed circuit board 116 from the underside of the basemember 76.

The foregoing arrangement provides support for the printed circuit board116 with a minimum of fasteners, and where maintenance of the board isrequired, it permits the board to be removed from the base member 76without disturbing the mechanical elements. Where maintenance of themechanical elements is required, it permits the board 116 to be removedas a unit with the base member 76 without disturbing the electricalelements on the board.

A plurality of electrical components are mounted on the underside of theprinted circuit board 1 16. These components in combination with thecommon switch 106 comprises a multifrequency signal generator of thecall transmitter. These components consist of resistors 122, 123, and124; varistors 125, 126, 127, and 128; capacitors 129, 130, and 131;transformers 132 and 133; and a transistor 134. Connections are madefrom the components to printed circuitry (not shown) on the uppersurface of the printed circuit board 116 by inserting the leads of thecomponents through small holes in the board. Mechanical connection aswell as electrical connection is then made by a process such as solderdipping.

To operate the call transmitter, the user lifts the handset from thecradle 16 and listens for a dial tone. Upon hearing a dial tone, hesequentially depresses the pushbuttons which correspond to the telephonenumber of the desired subscriber. Signal-s corresponding to thetelephone number are thereby transmitted to the central office.

Although the call transmitter as disclosed is not illuminated, it may beilluminated by the addition of a light bulb that is positioned adjacentto a reflector 121 depending from one corner of the cover member 48 andby the addition of a generally rectangular light guide that ispositioned between the frame member 75 and the base member and isconfined within the walls depending from the frame member. Thepushbuttons 20 would then be formed from a translucent material, and theopaque characters on the pushbuttons would be viewed against anilluminated background.

Although the code transmitter of the present invention has been shownand described in terms of being used as a call transmitter, it Will beunderstood that this is but one illustrative use. Other uses, as forexample, as a data transmitter, may be made thereof. In addition,various modifications may be made therein without departing from thescope and spirit of this invention as defined in the appended claims.

What is claimed is:

1. A code transmitter comprising:

a cover member having a plurality of holes therein arranged in an arrayof longitudinal columns and transverse rows, a plurality of guidecollars extending from the topside of the cover member and respectivelyencompassing the holes to increase the height of the walls defining theholes, the walls defining the holes tapering inwardly toward the upperends thereof, the cover member further having a plurality of contactprestressing studs extending from the underside of the cover member, thestuds being disposed just inside the periphery of the cover member;

a base member secured to the underside of the cover member;

a frame member sandwiched between the base member and the cover member,the frame member having an array of holes positioned in alignment withthe holes in the cover member;

an individual pushbutton situated in each of the holes a spring memberpositioned in the aperture of each pushbutton, the spring member bearingagainst the base member and biasing the pushbutton upwardly; pluralityof longitudinal and transverse rotatable shafts journaled in the covermember and retained in position by the frame member, an individual shaftextending along one side of each column and each row of pushbuttons,each shaft having a plurality of laterally projecting levers, theindividual levers on each shaft respectively extending: beneath theindividual flanges of the pushbuttons alongside of which the shaftextends;

plurality of pairs of spring contacts secured to the periphery of thebase member, each pair being associated with an individual shaft, onecontact of each pair being biased against one of the levers of itsassociated shaft, the other contact being biased against a contactprestressing stud of the cover member, each pair of spring contactsbeing positioned just within the periphery of the cover member;

an operator positioned between the frame member and the base member, theoperator being slidably displaceable along a channel in the underside ofthe frame member, the operator having a plurality of spaced camsurfaces, an individual cam surface being associated with eachtransverse shaft and being in juxtaposition with one of the levers ofits associated shaft, the operator further having a contact actuatingcomb portion extending through an aperture in the base member, the combportion having a plurality of dilferentially spaced teeth; and

a spring contact pileup secured to the underside of the base member, thespring contact pileup having individual spring contacts thereofrespectively extending into engagement with individual teeth of the combportion of the operator and being sequentially oper-ated by thedisplacement thereof.

In combination:

a cover member having a plurality of holes therein arranged in an arrayof longitudinal columns and transverse r-ows, a plurality of guidecollars extending from the topside of the cover member and respectivelyencompassing the holes to increase the height of the walls defining theholes, the walls defining the holes tapering inwardly toward the upperends thereof;

an individual pushbutton situated in each of the holes in the covermember, each pushbutton being movable in a path of travel between anextended position and a depressed position and being biased toward itsextended position;

two sets of rotatable shafts journaled in the cover member, one setextending generally perpendicular to the other set, an individual shaftof one set extending along one side of each column of the pushbuttonsand an individual shaft of the other set extending along one side ofeach row of the pushbuttons, each shaft having a plurality of laterallyprojecting levers, individual levers on each shaft respectivelyextending into the path of travel of the individual pushbuttonsalongside of which the shaft extends;

first plurality of pairs of contacts, each pair of contacts beingassociated with an individual shaft, one

contact of each pair being biased against one of the the displaceablemember and being sequentially oplevers of its associated shaft, eachpair of contacts erated by the displacement thereof. gelrilgbenpisltioned ust Within the periphery of the cover References Cited ythe Examiner a displaceable member having a plurality of spaced 5 UNITEDSTATES PATENTS cam surfaces, each cam surface being associated with2,358,586 9/ 1944 Newell 179--90.2 an individual shaft of one of thesets of shafts and 2,389,247 11/1945 Dowey 17990.3 being injuxtaposition with one of the levers of its 2,553,137 6/1951 MarriSOn17990.3 associated shaft, the displaceable member further 9, 1 /196M1tchell et a1. 179-90.3 having a contact actuating comb portion thecomb 10 3,120,584 2/1964 Grunfeldel' et 179-993 portion having aplurality of differentially spaced 3,123,676 3/1964 Prescott et 17990-3teeth; and KATHLEEN H. CLAFFY, Primary Examiner.

a second plurality of pairs of contacts having individual contactsthereof respectively extending into engage- 15 RICHARD MURRAY Examinemen-t with individual teeth of the comb portion of H. ZELLER, AssistantExaminer.

2. IN COMBINATION: A COVER MEMBER HAVING A PLURALITY OF HOLES THEREINARRANGED IN AN ARRAY OF LONGITUDINAL COLUMNS AND TRANSVERSE ROWS, APLURALITY OF GUIDE COLLARS EXTENDING FROM THE TOPSIDE OF THE COVERMEMBER AND RESPECTIVELY ENCOMPASSING THE HOLES TO INCREASE THE HEIGHT OFTHE WALLS DEFINING THE HOLES, THE WALLS DEFINING THE HOLES TAPERINGINWARDLY TOWARD THE UPPER END THEREOF; AN INDIVIDUAL PUSHBUTTON SITUATEDIN EACH OF THE HOLES IN THE COVER MEMBER, EACH PUSHBUTTOM BEING MOVABLEIN A PATH OF TRAVEL BETWEEN AN EXTENDED POSITION AND A DEPRESSEDPOSITION AND BEING BIASED TOWARD ITS EXTENDED POSITION; TWO SETS OFROTATABLE SHAFTS JOURNALED IN THE COVER MEMBER, ONE SET EXTENDINGGENERALLY PERPENDICULAR TO THE OTHER SET, AN INDIVIDUAL SHAFT OF ONE SETEXTENDING ALONG ONE SIDE OF EACH COLUMN OF THE PUSHBUTTONS AND ANINDIVIDUAL SHAFT OF THE OTHER SET EXTENDING ALONG ONE SIDE OF EACH ROWOF THE PUSHBUTTONS, EACH SHAFT HAVING A PLURALITY OF LATERALLYPROJECTING LEVERS, INDIVIDUAL LEVERS ON EACH SHAFT RESPECTIVELYEXTENDING INTO THE PATH OF TRAVEL OF THE INDIVIDUAL PUSHBUTTONSALONGSIDE OF WHICH THE SHAFT EXTENDS; A FIRST PLURALITY OF PAIRS OFCONTACTS, EACH PAIR OF CONTACTS BEING ASSOCIATED WITH AN INDIVIDUALSHAFT, ONE CONTACT OF EACH PAIR BEING BIASED AGAINST ONE OF THE LEVERSOF ITS ASSOCIATED SHAFT, EACH PAIR OF CONTACTS BEING POSITIONED JUSTWITHIN THE PERIPHERY OF THE COVER MEMBER; A DISPLACEABLE MEMBER HAVING APLURALITY OF SPACED CAM SURFACES, EACH CAM SURFACE BEING ASSOCIATED WITHAN INDIVIDUAL SHAFT OF ONE OF THE SETS OF SHAFTS AND BEING INJUXTAPOSITION WITH ONE OF THE LEVERS OF ITS ASSOCIATED SHAFT, THEDISPLACEABLE MEMBER FURTHER HAVING A CONTACT ACTUATING COMB PORTION THECOMB PORTION HAVING A PLURALITY OF DIFFERENTIALLY SPACED TEETH; AND ASECOND PLURALITY OF PAIRS OF CONTACTS HAVING INDIVIDUAL CONTACTS THEREOFRESPECTIVELY EXTENDING INTO ENGAGEMENT WITH INDIVIDUAL TEETH OF THE COMBPORTION OF THE DISPLACEABLE MEMBER AND BEING SEQUENTIALLY OPERATED BYTHE DISPLACEMENT THEREOF.